Armor forbidden to all but the best warriors.
Supposedly, a vest that belonged to a demon.
Demon's Vest is a high-ranked light armor that provides 31 Defense, +1 Magic, halves Shadow-elemental damage, and teaches Auto-Potion, Devil Killer, and Locomotion. It can be bought for 10,250 gil at Daguerreo (disc 3), Ipsen's Castle, and Bran Bal, found on Terra, or stolen from Meltigemini. It can be equipped by everyone except Steiner and Freya.
Gigas Chestplate is a high-ranked light armor that requires the Light Armor 9 license to equip, and provides 38 Evade, +540 HP, and +2 Magic. It can be bought for 10,700 gil at Balfonheim Port or from the Bazaar from the "Gigas Gear" set, and dropped by Molen (3% chance).
In the International version, it now provides 47 Evade, and can now, in addition to the previous methods, be found at the Ridorana Cataract (Echoes from Time's Garden).
Gigas Chestplate is the strongest armor for Vaan, providing in its base form 90 Defense, 60 Magick Defense, +10 Strength, and +15 Speed. It is a reward after completing Mission 78: Masterless Minions.
Demon's Vest is a level 100 chestplate that provides +2645 HP, +79 Bravery, -1 Defense, and BRV Boost on Stage Destruction +5%. It can be obtained from the shop by trading 137,100 gil, Mirror Mail, Viking Mail, and Shinryu Claw.
demon is "an evil spirit or devil, especially one thought to possess a person or act as a tormentor in hell."A